基于ADS—33E的直升机解耦控制律设计与仿真

对直升机各控制通道间耦合严重的特点,基于前馈补偿方法设计直升机解耦控制系统;分析、比较直升机各通道之间的耦合效应,确定解耦控制器结构;针对不同高度和速度下的飞机模型设计解耦控制律,利用径向基神经网络拟合控制参数,实现全包线范围内的解耦控制律,并仿真验证;依据飞行品质规范ADS—33E可以得出,采用上述控制方案,可以取得良好的解耦控制效果,表明了该方法的可行性和有效性。     

小型无人直升机姿态非线性鲁棒控制设计

本文针对小型无人直升机的姿态控制问题,通过系统参数辨识,获得了较为准确的无人直升机姿态动力学模型.并根据无人直升机的动态特性,设计了基于神经网络前馈与滑模控制的非线性鲁棒姿态控制律,该控制律对直升机模型的先验知识要求较低.利用基于Lyapunov的分析方法证明,设计的控制律能够实现对无人直升机姿态角的半全局指数收敛镇定控制,并能确保闭环系统的稳定性.基于姿态飞行控制实验平台的实时飞行控制实验结果表明,提出的控制设计取得了很好的姿态控制效果,并对系统不确定性和外界风扰动具有较好的鲁棒性.     

小型无人直升机悬停小速度段位置控制技术

无人直升机在悬停/小速度飞行阶段具有特殊的物理特性,给控制系统的设计带来了诸多技术难题;针对无人直升机悬停/小速度段位置控制的需求,提出了一种基于"姿态角阻尼内回路"的位置控制结构,该控制结构采用内回路姿态角阻尼增稳,外回路位置控制的控制方式;并且针对增稳回路自适应性、抗风补偿和位置控制精度等问题,分别采用前馈自动配平机制与非线性PID控制方法对常规控制律进行改进;仿真验证表明,所提出的控制策略和控制律设计结果达到了较好的控制效果。     

基于LQR的无人直升机姿态控制器设计

无人直升机控制系统是一个易受环境干扰的、各通道相互耦合的非线性系统.为了实现无人直升机能在不同环境下自主飞行,需要设计抗干扰能力强的控制器;采用系统辨识的方法得到直升机横向通道和纵向通道姿态环路的线性系统模型;根据线性最优二次型理论,对直升机横向通道和纵向通道的姿态环路设计了LQR最优控制器,使用MATIAB仿真选取最优控制器参数后,在ALIGN 700N直升机上进行了实际飞行试验,仿真和飞行试验表明,采用LQR控制技术设计的无人直升机姿态控制器具有较强的鲁棒性和实用性.     

无人直升机位置平移策略浅谈

位置平移策略影响无人直升机前后左右位置平移的安全及功能实现,是完成无人直升机纵横向位置平移功能的前提条件。本文针对无人直升机纵横位置平移的飞行任务需求,结合无人直升机悬停小速度段的气动特性,给出了纵横通道位置控制结构及纵横向位置平移策略,不仅实现了纵横向位置平移的功能,还满足了悬停与前飞安全过渡的需求,在保证安全的同时实现了无人直升机小速度左右侧飞。     

无人汽油直升机偏航角测量的设计与实现

为了提高无人直升机的控制性能,实现无人直升机的长距离稳定飞行,针对所采用的汽油动力无人直升机对航向角测量传感器的影响干扰,结合RS232和TWI通信方式,设计和实现基于HMC5883L三轴数字罗盘的偏航角的稳定测量;实验验证和实际飞行表明,此次设计所测量的偏航角数据准确,响应速度快,且不受汽油机电磁干扰的影响,具有很好的稳定性。     

直升机飞行控制器设计与仿真

为了改善直升机飞行控制系统的性能,研究了其在前飞状态下的模糊平滑切换控制方法和仿真验证问题。以ADS-33D水平1操纵品质要求为设计目标,建立直升机不同平衡点的线性子模型,采用基于遗传算法的H∞控制器设计方法设计各局部控制器,应用模糊平滑切换策略设计全局控制器,实现直升机在不同速度下的飞行控制,保证了控制过程的平滑性,并用数学方法证明了系统的稳定性。仿真结果表明,所设计的直升机飞行控制器达到了ADS-33D水平1操纵品质要求。     

小型无人直升机的无模型自适应鲁棒控制设计

本文针对小型无人直升机的姿态控制问题,考虑到现有基于模型的控制方法对系统动力学模型的依赖性,以及未建模动态对系统控制性能的影响,设计了一种新的基于数据驱动的无模型自适应鲁棒控制律.通过基于数据驱动的设计方法,降低了控制器对直升机动力学模型先验知识的依赖,补偿了未建模不确定性的影响.仅利用无人直升机的输入输出数据,即可实现对无人直升机系统的稳定姿态控制.然后本文结合离散滑模控制设计,补偿了未知外界扰动的影响,提高了系统的鲁棒性,并通过理论证明了控制误差的收敛性和闭环系统的稳定性.最后,在本研究组自主开发的无人直升机飞行控制实验平台上,进行了无人机实时控制实验.实验结果表明,本文所提出的控制算法取得了很好的姿态控制效果,并对系统不确定性和外界风扰动具有良好的鲁棒性.     

小型无人直升机的数学建模与仿真

小型无人直升机是一个复杂的非线性系统.为了真正实现小型无人直升机的自主飞行,须对其进行精确的数学建模.本文以Raptor90小型无人直升机为研究平台,综合考虑了直升机在不同飞行模态下的飞行特性,利用基于叶素理论的积分算法,对直升机进行非线性建模,并对所建模型进行数值仿真.仿真结果表明,所建模型能够较好的反应直升机的动态响应特性,所建模型具有较高精度,可基于此模型进行飞行控制器的设计.     

一种小型无人直升机自主起飞控制方法

针对小型无人直升机(Small-scale unmanned helicopter, SUH) 起飞过程中过度依赖于地面飞行手的问题, 提出了一种基于经验知识与系统辨识的自主起飞控制方法. 首先, 通过研究专业飞行手手动操纵小型无人直升机起飞过程中高度与油门、总距舵量等信息的对应关系, 分析了利用学习飞行手的操纵行为实现小型无人直升机自主起飞的可行性, 并设计了小型无人直升机自主起飞控制流程. 引入了安全高度及变增益控制以提高自主起飞过程中的飞行安全性能, 利用不完全微分控制方法抑制了微分高频噪声. 其次, 为了获取自主起飞过程中控制参数, 采用自适应遗传算法对小型无人直升机动力学模型进行了辨识, 在动力学模型的基础上进一步辨识得到了飞行控制参数. 最后, 通过在小型无人直升机平台进行的实际飞行实验, 验证了本文方法的有效性.     

A fuzzy gain-scheduler for the attitude control of an unmanned helicopter

In this paper, we address the design of an attitude controller that achieves stable, and robust aggressive maneuverability for an unmanned helicopter. The controller proposed is in the form of a fuzzy gain-scheduler, and is used for stable and robust altitude, roll, pitch, and yaw control. The controller is obtained from a realistic nonlinear multiple-input-multiple-output model of a real unmanned helicopter platform, the APID-MK3. The results of this work are illustrated by extensive simulation, showing that the objective of aggressive, and robust maneuverability has been achieved.     

基于Dubins曲线的无人直升机轨迹规划

为提高无人直升机的控制性能,提出了一种基于Dubins曲线的轨迹规划算法,并对其各个部分的实现进行了研究和设计。该算法利用Dubins曲线原理对定点飞行任务的两点或者多点目标进行分析计算,寻找出一条最短的飞行路径,从而提高了飞行效率。根据无人直升机系统多变量、非线性和强耦合的特点,采用串级PID方法设计了飞行控制器,该控制器能够修正无人直升机的姿态和位置,从而提高了轨迹规划的稳定性和准确性。最后,以某小型无人直升机为实验平台表明了该轨迹规划算法和控制器的可行性。     

Trajectory linearization control for a miniature unmanned helicopter

Trajectory linearization control (TLC) approach is applied to design a nonlinear trajectory tracking controller for a miniature unmanned helicopter. The controller is based on nonlinear model derived from Newton-Euler equations, with collective and cyclic pitches being regarded as actual controls. Via model simplifications, the nonlinear helicopter model can be transformed into a cascaded form including four subsystems. Corresponding with the simplified cascaded structure, the proposed controller is constructed by synthesizing TLC designs for subsystems. Each of them includes designs of a pseudo-inversion and an error regulator. A summarized TLC algorithm for the unmanned helicopter is listed briefly after the detailed controller design process. Simulation results are provided to demonstrate performances of the closed-loop system.     

Autonomous takeoff and landing control for a prototype unmanned helicopter

In this paper, an autonomous takeoff and landing control strategy is designed and implemented for a prototype coaxial unmanned helicopter with ducted fan configuration. The control strategy is designed such that longitudinal and lateral controls use ground forces, attitude and drifting feedbacks. Vertical control employs takeoff and landing decision and vertical velocity control is based on altitude tracking. Ground forces feedback is used to balance longitudinal forces and moments during liftoff effectively cancelling all ground forces. Attitude and drifting feedbacks are used to balance the longitudinal and lateral movements of the helicopter during takeoff and landing. The flight control strategy is successfully verified during flight tests.     

小型无人直升机发动机转速控制系统设计

良好的活塞式汽油发动机控制系统是小型无人直升机稳定飞行和保持恒定转速的前提条件.本文针对某型无人直升机发动机控制系统中采用的GV-1进行控制器参数的辨识,最后基于自抗扰控制技术设计出简单、可靠和成本低廉的转速控制器,实验结果表明,该控制器可以到达稳定飞行的需要.验证了所设计的控制器的有效性,可进一步简化小型无人机的转速...     

Trajectory linearization based output tracking control of an unmanned tandem helicopter with variance constraints

An output tracking control problem for an unmanned tandem rotor helicopter with variance constraints is investigated in this paper. A modified Trajectory Linearization Control (TLC) is proposed to stabilize a nonlinear continuous-time flight dynamics system of the tandem helicopter. The tracking controller structure of TLC is designed by using two-time-scale nonlinear dynamic inversion. The base control law of the translational and attitude loops is designed in a pseudo-inversion feedforward controller to deal with nonlinear features of the plant and a proportional integral controller to stabilize the linear slowly time-variant error system resulted from the nonlinear flight system. Furthermore, a feasible TLC strategy is designed to meet a performance index set including steady trajectory tracking error variance and desired Parallel D-spectrum (PD-) eigenvalues to achieve good flight quality. The Variance-constrained Trajectory Linearization Control (VCTLC) is designed to realize the desired steady tracking precision and agile capability. Flight simulation results show the VCTLC method is feasible and effective in attitude and altitude tracking.     

Robust multi-mode flight control design for an unmanned helicopter based on multi-loop structure

In this paper, a novel multi-mode flight control strategy for unmanned helicopter, in presence of model uncertainty, atmospheric disturbances and handling qualities specification requirements (as in ADS-33E), based on multi-loop control structure combining robust H-infinity and PI control is presented. In inner loop H-infinity optimal control technique is utilized ensuring the stability of flight control system in case of change of helicopter dynamics, model uncertainties and eliminates effect of gust disturbance on helicopter states and collective/cyclic inputs. PI control in outer loop is used to improve the dynamic and static operation characteristics. Attitude control and attitude holding flight mode with satisfactory command response and decoupling characteristics is designed using the proposed control strategy. Analysis and simulation results show that Level 1 handling requirements as defined in ADS-33E are accomplished even when helicopter is under constant wind circumstance.     

遥控模型直升机分通道模型辨识方法研究

设计了嵌入式控制系统,研究了小型遥控直升飞机在悬停状态的模型辨识方法.按照遥控直升机的4个控制输入(纵向周期变距、横向周期变距、总距、以及尾距),直升机的运动可分解为俯仰、倾斜、升降和航向4个通道,分别采用分通道飞行实验数据,通过Matlab辨识工具,得到了遥控直升机在悬停状态下各通道的单榆入单输出控制模型.飞行实验数据的验证结果表明,分通道数学模型可以很好地反映相应通道的动态特性,对实现遥控直升机自动驾驶控制具有重要的应用价值.     

Nonlinear robust control of a quadrotor helicopter with finite time convergence

In this paper, the control problem for a quadrotor helicopter which is subjected to modeling uncertainties and unknown external disturbance is investigated. A new nonlinear robust control strategy is proposed. First, a nonlinear complementary filter is developed to fuse the raw data from the onboard barometer and the accelerometer to decrease the negative effects from the noise associated with the low-cost onboard sensors Then the adaptive super-twisting methodology is combined with a backstepping method to formulate the nonlinear robust controller for the quadrotor''s attitude angles and the altitude position. Lyapunov based stability analysis shows that finite time convergence is ensured for the closed-loop operation of the quadrotor''s roll angle, pitch angle, row angle and the altitude position. Real-time flight experimental results, which are performed on a quadrotor flight testbed, are included to demonstrate the good control performance of the proposed control methodology.